Bio-polyols are made of vegetable oil and are epoxidized and hydroxylated by using unsaturated double bond, wherein epoxy is ring-opening hydroxylated by strong acids, such as sulfuric acid (as disclosed in U.S. Pat. No. 9,216,940), boron trifluoride (BF3), tetrafluoroboric acid (as disclosed in U.S. Pat. No. 6,433,121), phosphate (as disclosed in US Patent No. CN104672113). However, such strong acids has high causticity, causes carbonization of raw materials or products, is non-recyclable. In addition, strong alkali solution is used after epoxy is ring-opening hydroxylated to increase manufacture cost and produce waste water, wherein boron trifluoride makes smokes in humid air and is toxic. To overcome such a problem, solid acid catalyst (as disclosed in CN 104725210) is hydroxylated and is synthesized from zeolite, kaolin, and montmorillonite to produce polyols.
Alternatively, inorganic catalyst (such as alkali metal hydroxide or alkali metal alkoxide) or organic alkali (such as organic amine compound) is ring-opening hydroxylated as disclosed in CN Publication Nos. CN 100465152, CN 100390128, and CN101125912, wherein corrosion to reaction tank or pipes is evitable by using organic alkali, but the organic alkali is neutralized by ways acidic substances of and is absorbed by using adsorbent, thus increasing cost. Furthermore, the catalyst is not recycled.
Acidic ionic liquid is applicable for catalytic esterification, transesterification, epoxidation (as disclosed in CN Publication Nos. CN 101735175 and CN 102787007), and ring-opening hydroxylation (as disclosed in CN Publication No. CN 104341297) to be recyclable after reacting process.
When above-mentioned treatment takes long time, the patient will feel uncomfortable, because conducting current repeatedly.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.